Yeah, I would act weird on a date. Actually, I have been out on a few formal dates, but it wasn't something I really wanted. The guys asked me and I wasn't into them but I was flattered so I went. I talked too much, didn't learn anything about them, discovered I wasn't particularly attracted to them, felt patronized when they wanted to pay (and annoyed that we had gone to a pricey restaurant...as strangers)
For me, I just don't know how to be casual. I guess I'm afraid of being taken advantage of in some way... I'd want to get to know someone as a friend first... Or at least feel powerful enough to decide what happens. I overthink things a lot.
I guess to really formally be dating, for me I would want to be friends with the person.